virtualbox.org

When I am running VirtualBox on Ubuntu Hardy Heron (8.04), the VM and other running applications (e.g. firefox, rhythmbox, etc) often hangs frequently for a few seconds, especially under conditions of heavy disk IO. When the system hangs, I see the following error messages repeating over and over:

[ 3999.283710] ata1.00: status: { DRDY ERR }
[ 3999.283712] ata1.00: error: { UNC }
[ 3999.287278] ata1.00: configured for UDMA/100
[ 3999.287289] ata1: EH complete
[ 4002.190218] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0
[ 4002.190225] ata1.00: irq_stat 0x40000001
[ 4002.190250] ata1.00: cmd c8/00:b8:c8:74:a0/00:00:00:00:00/e6 tag 0 dma 94208 in
[ 4005.096762] ata1.00: status: { DRDY ERR }
[ 4005.096765] ata1.00: error: { UNC }
[ 4005.100329] ata1.00: configured for UDMA/100
[ 4005.100357] Descriptor sense data with sense descriptors (in hex):
[ 4005.100413] ata1: EH complete

The only time I ever see these error messages is when VirtualBox is running. Any advice on how to fix this issue?

What version are you running? If you read the 1.6.6 announcement you will see a couple of the fixes are in this area.

I'm running version 1.6.6.

Just to be sure you get these errors on the host right? The fixes are for the emulated SATA controller in VirtualBox and wouldn't help there. I doubt that VirtualBox is the cause but probably triggers a bug in the kernel driver of your storage controller when having a high I/O load.
Can you try to reproduce this on another computer under the same conditions?